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Blue and White Supergiants
Blue and White Supergiants 'are stars with spectral classifications from W (Wolf-Rayet Stars) to A, giving them temperatures between 200,000 to 7,000 degrees Kelvin. They are extremely rare in the universe, with them being less than 0,001% of stars in the universe. This article will cover a few famous examples of blue supergiant stars. For blue supergiant stars that are luminous blue variables, see Luminous Blue Variables. Deneb Deneb, also known as Alpha Cygni, is the brightest star in the constellation of Cygnus. It is the 19th brightest star in the night sky, with an apparent magnitude of 1.25 . A blue-white supergiant, Deneb is also one of the most luminous stars. However, its exact distance and luminosity have been hard to calculate; it is estimated to be somewhere between 54,000 and 196,000 times as luminous as the Sun. Properties Deneb's absolute magnitude is currently estimated as −8.4 , placing it among the most luminous stars known, with an estimated luminosity nearly 200,000 times that of the Sun. This is towards the upper end of various published values over the last few decades. Based on its temperature and luminosity, and also on direct measurements of its tiny angular diameter (a mere 0.002 second of arc), Deneb appears to have a diameter of about between 100 to 200 times that of the Sun; if placed at the center of the Solar System, Deneb would extend out to the orbit of the Earth. It is one of the largest known white stars. Rigel Rigel is a hot supergiant star in the Milky Way Galaxy. It is classified as a blue supergiant. It is located in the constellation Orion. Many scientists believe that Rigel was the youngest star in the constellation. Rigel lies 778 light-years from Earth in Orion. It is visible from Earth as a small, bluish circle on clear nights from both hemispheres. It is between 120,000 and 279,000 times brighter than the Sun. Rigel is much bigger than our star here in the solar system, the Sun at between 78 and 115 times its radius. Rigel is actually in a triple star system, with two stars orbiting it at a distance of 14 billion kilometers! Canopus |size = 71 ± 4https://academic.oup.com/mnras/article/434/1/437/999630 |luminosity = 10,700 |temperature = 6,998 K|image1 = Sirius-0.JPG|constellation = Carina|apparent_magnitude = -0.74}}Canopus, also known as Alpha Carinae, is a white giant star located 310 light years away in the constellation Carina. It is the second brightest star in the night sky with an apparent magnitude of -0.74. It is only visible in latitudes below 37°31 . It was named after a servant of a king of Sparta. See also * Sirius Iota Carinae Iota Carinae is a white supergiant with spectral classification A 9 .http://adsabs.harvard.edu/abs/1975mcts.book.....H It is a suspected variable starhttps://doi.org/10.1134%2FS1063773706090052 located 690 light years away from the Sun in the It has a luminosity of , a mass of , a temperature of 7,500 degrees Kelvin and a diameter of Calculated from the mean temperature and luminosity: \sqrt{((5772/7500)^4 * 4900)} = 41.4598912001https://doi.org/10.1051%2F0004-6361%3A20054377 In Chinese, 海石 (Hǎi Shí), meaning Sea Rock, refers to an asterism consisting of Iota Carinae, Avior, HD 83183, l Carinae and Upsilon Carinae.中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7. Consequently, Iota Carinae itself is known as 海石二 (Hǎi Shí èr, the second of the Sea Rock).香港太空館 - 研究資源 - 亮星中英對照表 Stars of Orion's Belt 's impression of Mintaka]] The belt of Orion is the most prominent feature of the Orion constellation. It consists of the blue supergiant stars Alnitak, Alnilam, and Mintaka. Properties Table (Radius, luminosity, mass) Gamma Velorum Gamma Velorum '''is a star system consisting of blue stars located in the Vela constellation. Properties This blue star is also sometimes known as Regor - «Roger» spelled backwards, in honor of the astronaut Roger Chaffee, who died in a fire during a routine test onboard the Apollo 1 spacecraft in 1967. Gamma Velorum is a complex star system dominated by a blue subgiant that is poised to evolve off the main sequence. Its evolution has been affected by being in a very close binary orbit with a star that is a Wolf-Rayet star. They lie as close as Earth is to the Sun and orbit each other every 78.5 days. The Wolf-Rayet star is the less massive component of the binary, but started more massive than the blue subgiant but lost mass and evolved quickly. The subgiant is 30 times the Sun's mass and has a surface temperature of 35,270 degrees Kelvin, and a luminosity 20,000 times greater than the Sun. The subgiant is 17 times the diameter of the Sun. Icarus '''Icarus is the name given to the most distant star ever observed from the Earth. It is located 9 billion light years away, so when it was discovered by NASA on April 2018, it was observed as it was 9 billion years ago. It is believed to be a blue supergiant. References * ISBN 978-1-4093-7650-7 * https://academic.oup.com/mnras/article/377/1/415/1746933 * https://www.aanda.org/articles/aa/abs/2010/13/aa14509-10/aa14509-10.html * http://adsabs.harvard.edu/abs/2009yCat....102025S * http://adsabs.harvard.edu/abs/1978ApJ...223..207L * https://www.aanda.org/articles/aa/abs/2010/13/aa14509-10/aa14509-10.html * https://doi.org/10.1051%2F0004-6361%3A20078590 * http://iopscience.iop.org/article/10.1088/0004-637X/747/2/108/meta * http://iopscience.iop.org/article/10.1088/0004-637X/747/2/108/meta * https://www.aanda.org/articles/aa/abs/2014/06/aa22894-13/aa22894-13.html * https://www.livescience.com/62205-most-distant-star-ever-seen.html * ISBN 978-1-4093-7650-7 * https://academic.oup.com/mnras/article/377/1/415/1746933 Category:Astronomy Category:Stars Category:B-type supergiants Category:B-type hypergiants Category:Semiregular variable stars Category:Stars of Orion Category:Stars with uncertain parameters